ES2311057T3 - PROCEDURE FOR THE FORMATION OF EMULSIONS. - Google Patents

Abstract

A process for the production of an oil-in-water emulsion having a discontinuous oil phase and a continuous aqueous phase, a process comprising a cross-linking reaction step between (i) a polymeric stabilizer of formula (I) which is a copolymer of random grafting or a block copolymer and comprising a series of vinyl monomers that are not exclusively vinyl esters or their hydrolyzed products, and that is soluble or dispersible in the continuous phase (See formula) where Z is a methoxy-polyethylene glycol group ; R1, R and R2 are independently H or methyl; X is a hydrophilic functional moiety; L is a moiety that contains a crosslinking group capable of undergoing nucleophilic crosslinking or condensation reactions at the interface of the dispersed and continuous phases of said emulsion, wherein said crosslinking group is selected from -OH; -NHA wherein A is hydrogen or C1-C4 alkyl; and -COOH or a salt thereof; And it is a hydrophobic residue; the value of e ranges from 0.005 to 0.33; the value of f ranges from 0.05 to 0.4; and the value of g ranges from 0.1 to 0.9; and (ii) one or more substances dissolved in the discontinuous liquid oil phase that reacts with the crosslinking group of the functional moiety L; provided that when the crosslinking group of the moiety L is a reactive acid group, the substance (ii) has its corresponding reactive group isocyanate, aziridine or carbodiimide.

Description

Procedure for the formation of emulsions

This invention relates to the use of polymeric surfactants reactive in the formation of emulsions and more specifically to the use of reactive polymeric surfactants in the formation of emulsions used to prepare products microencapsulated

The reactive polymeric surfactants for its use in this invention (also referred to herein polymer stabilizers memory) generally have three functional moieties - a hydrophilic moiety, a hydrophobic moiety and a  remainder that has reactive or crosslinking capacity with respect to a monomeric or prepolymeric substance, or with respect to a ingredient selected from the dispersed phase of the emulsion. When these surfactants are used with a discontinuous phase dispersed in a predominantly aqueous continuous phase, the hydrophobic moiety is strongly adsorb to the surface of the discontinuous phase while that the hydrophilic moiety is strongly associated with the aqueous phase, thereby conferring colloidal stability to the phase discontinuous Crosslinking moieties allow the surfactant react or bind to the monomer or polymer, or other ingredient mentioned above while the stabilizing remains of surfactant colloids provide surface properties active to the combination of surfactant / monomer or polymer. The Emulsions according to the invention can be used for a variety of purposes that include the formulation of agrochemical ingredients assets. As described below, surfactants for its use in this invention provide characteristics of combination / active surface similar when used with emulsions used to prepare products microencapsulated

Surfactants for use in this invention will be select between certain graft copolymers and certain random block copolymers. Notably graft copolymers and random block copolymers for use in the present invention are surfactants themselves same that bind to the interface of the emulsion by reaction of crosslinking residue.

Emulsions are types of agricultural formulation important, for example such as emulsions oil-in-water (EW) or components of suspo-emulsions (SE) comprising an EW and a suspension concentrate (SC). Emulsions can become unstable for a number of reasons being able to coalesce, flocculate or settling Such phenomena are not desirable and can complicate or Avoid using the formulation. Therefore, a considerable effort to understand how to induce stability by methods such as density adjustment, producing distributions narrow particle size to limit pore collapse (phenomenon called "Ostwald ripening"), and using the optimal colloidal surfactants and stabilizers. The phenomenon of Ostwald ripening in emulsions may be favored by surfactants that can carry the oil drop by drop through the phase continues, for example in micelles. The Ostwald phenomenon ripening can be avoided or inhibited by employing surfactants that do not form such carriers or that are fixed to the interface of the emulsion.

Conventional emulsion surfactants that they physically adsorb to the interface between the discontinuous phases and continuous can be displaced by competitive desorption by other surface active agents that can be added to the formulation, or by conditions that force the formulation, by example temperature and electrolyte concentration cycles.

We have discovered that the stability of Emulsions can be improved when the surfactants are fixed to the interface of the emulsion according to the present invention. Foam formation is also eliminated when there is no free surfactant in the continuous phase.

The micro-encapsulation is a well known technique used to prepare solid particles that they contain inside a core that includes materials liquids and / or solids derived from a liquid emulsion phase scattered Thus, the liquid materials of the core can be liquids themselves, or liquids containing dissolved solids or suspended in them. Depending on the design of the microcapsule, the Interior material can be released in a controlled manner, slow, or in a quick release. There are numerous techniques well known to design the content and nature of the wall polymeric microcapsule in order to achieve the results desired In the agricultural field, these microcapsules are used with pesticides such as herbicides, insecticides, fungicides and bactericides, with plant growth regulators and with fertilizers Non-agricultural uses include dyes, inks, pharmaceuticals, flavoring agents and fragrances encapsulated, where the encapsulated medium is present in the form of liquid core.

The materials used in the formation of Microcapsule walls are usually intermediate or resin monomers. In the prior art they have been developed and described several processes for the microencapsulation of materials. These processes can be divided into three broad categories - physical methods, phase separation and interfacial reaction. The methods of phase separation and interfacial reaction generally they pass through the formation of an emulsion, and therefore they are of particular relevance to the process of present invention

In a process of the separation category of phases, microcapsules are formed by emulsion or dispersion of the core material in an immiscible continuous phase in which the wall material dissolves, and then separates physically of the continuous phase, for example, by coacervation, and is deposited around the core particles. In the interfacial reaction category, the core material is emulsifies or disperses in a continuous immiscible phase; to then an interfacial polymerization reaction is triggered on the surface of the core particles, forming microcapsules

Interfacial polymerization reaction methods have proven to be the most suitable processes for use in the agricultural industry in pesticide microencapsulation. There are several types of interfacial reaction techniques. In a type of microencapsulation process by interfacial condensation polymerization, monomers of the aqueous and oleaginous phases are contacted at the oil / water interface, where they react by condensation to form the microcapsule wall. In another type of polymerization reaction, the in situ interfacial condensation polymerization reaction, all wall-forming monomers or prepolymers are contained in the oil phase. The oil is then dispersed in a continuous phase comprising water and a surface active agent. The organic phase is dispersed in the form of discrete drops throughout the aqueous phase by means of an emulsion, forming an interface between the discrete drops of the organic phase and the continuous phase of aqueous solution that surrounds them. The in situ condensation of the wall-forming materials and the maturation of the polymers at the interface of the organic-aqueous phases can be initiated by heating the emulsion to a temperature between about 20 ° C and about 100 ° C, optionally with a pH adjustment . The heating is applied for a period of time sufficient to allow a substantial realization of the in situ condensation of the wall-forming monomers or prepolymers that convert the organic drops into capsules consisting of solid sheaths of permeable polymer that enclose the materials of the organic core. .

One type of microcapsule prepared by in situ condensation and known in the art is that presented in US Pat. 4,956,129 and 5,332,584, which are incorporated herein by reference. Said microcapsules, usually referred to as "aminoplast" microcapsules, are prepared by self-condensation of etherified urea-formaldehyde resins or prepolymers in which between about 50% and about 98% of the methylol groups have been etherified with a C_ alcohol. {4} -C10 (preferably n-butanol). The prepolymer is added or included in the organic phase of an oil / water emulsion. The self-condensation of the prepolymer takes place by heat action at low pH.

To form the microcapsules, the temperature of the emulsion rises to a value between approximately 20 ° C and about 90 ° C, preferably between about 40 ° C and about 90 ° C, more preferably between about 40 ° C and approximately 60 ° C. Depending on the system, the value of pH can be adjusted to an appropriate level. For the purpose of this invention, a pH of about 2 is appropriate.

Another type of microcapsule prepared by in situ condensation and described in US Pat. 4,285,720, incorporated herein by reference, is a polyurea microcapsule that involves the use of at least one polyisocyanate such as polymethylene polyphenylene isocyanate (PMPPI) and / or tolylene diisocyanate (TDI) as wall forming materials. In the process described in said patent, the wall formation reaction is initiated by heating the emulsion to an elevated temperature, at which point the isocyanate groups hydrolyze at the oil / water interface to form amines, which in turn react with Isocyanate groups not hydrolyzed to form the wall of the polyurea microcapsule.

In another type of polymerization process interfacial, as mentioned before, the materials wall formers are contained in both phases of the emulsion, Organic and aqueous Said process is described, for example, in the U.S. Patent 4,280,833 in which an isocyanate such as the PMPPI is contained in the organic phase and such a reactive amine as hexamethylenediamine is contained in the aqueous phase. The two wall-forming materials react at the interface between the two phases to produce a polyurea microcapsule sheath that contains or encloses the materials to be encapsulated, which in turn are contained in the organic phase of the emulsion.

In most of these types of processes microencapsulation, external surfactants and / or others are used surface active agents such as emulsifiers or colloidal stabilizers. These materials, in fact, are used both in the processes of preparation of microcapsules and in the formulations resulting from them or produced from the same. The emulsifier serves to reduce stress surface between the oil and water phases, while the colloidal stabilizer serves to ensure that the particles are They keep separate. In the emulsification process, the size of gout is mainly controlled through the degree of shear applied and of the type and amount of emulsifier used. If it exists a significant competition between the emulsifier and the colloidal stabilizer in adsorption on the drop of oil, the colloidal stabilizer can be displaced, which leads to the coalescence of gout. After capsule formation, generally the same colloidal stabilizer must stabilize a solid particle that has different properties from those of gout of starting oil. If the colloidal stabilizer is displaced from the surface of the capsule, the capsules can agglomerate irreversibly; Some protective colloids are described, by example, in US Pat. 4,448,929 and 4,456,569, along with the aforementioned patents describing processes of microencapsulation Similarly, agents are needed superficially active in formulations made from microcapsules For example, the products of the processes of Typical microencapsulation are suspensions of the microcapsules in the aqueous phase (generally referred to as "suspensions of capsules "). In some cases, the capsule suspension will will package and sell as such. However, in that case it requires storing and transporting substantial amounts of water or other liquid Therefore, another technique involves producing a product of microcapsules (for example by spray drying or film-dried capsule suspension) and then sell a dry microcapsule product, both powder and any other solid form, such as tablets, granules extruded, etc. In all these cases, the product is designed to be mixed with water or to form a sprayable suspension of microcapsules In order to make the suspension sprayable (prepared from powder, granules, or other form of microcapsules) be relatively uniform to provide a product evenly substantially substantially when sprayed, it is necessary that the microcapsules disperse well in water The inclusion of superficially active agents in the product as it is sold, or the addition of agents superficially assets to the applicator spray tank or other spray equipment, it is often necessary to meet this purpose

In all the above mentioned uses of superficially active agents, certain defects or disadvantages. A typical one is that an agent superficially active can dissociate from the particles with the That is supposed to interact. This may occur in the emulsion or in the formation of the emulsion, or in the production or microcapsule formulation. In that case, the effectiveness of surface active agents decreases or is lost because the particle size uniformity or the particle dispersibility.

The properties of these agent materials superficially active are determined by the composition and the quantity of its hydrophobic and hydrophilic components. When the formulation comprises a discontinuous oil phase dispersed in a discontinuous aqueous phase, the hydrophobic components of the surface active agents must be strongly adsorbed on the surface of the discontinuous phase while the components hydrophilic surface active agents should provide colloidal stability, thereby preventing the discontinuous phase agglomerate.

The compositions and methods of preparation of polymeric surfactants are multiple and varied. A review of these materials can be found in the Piirma text: Polymeric Surfactants , Surfactant Science Series 42, (Marcel Dekker, New York, 1992). The two main classes of polymeric surfactants are those prepared as hydrophilic-hydrophobic blocks and those prepared as combinations of hydrophilic arms attached to a hydrophobic main chain, and vice versa. Said hydrophobic-hydrophilic polymers have been referred to as "amphipathic" or "amphiphilic." Adsorption of the discontinuous phase is maximized when surfactants have little or no tendency to form micelles in the continuous phase.

In general, polymeric surfactants can be manufactured by modifying pre-prepared polymers or by polymerization in a single stage or in a stepwise process. By For example, block copolymers can be manufactured by (i) step-controlled polymerization of, first, monomers hydrophobic and, secondly, of hydrophilic monomers, or the reverse process, or by (ii) the coupling of materials preformed hydrophobic and hydrophilic of adequate molecular weight. Graft copolymers can be manufactured by (i) graft polymerization of hydrophilic monomers or macromonomers to a hydrophobic main chain, or the reverse process, or by (ii) chemical conversion of suitable monomers that have been copolymerized with hydrophobic or hydrophilic monomers of the main chain Polymers that have properties surfactants similar to graft copolymers can be manufactured randomly copolymerizing hydrophilic monomers and hydrophobic or hydrophilic macromers and macromers hydrophobic

The preferred method of preparation for any given composition will depend on the nature and the properties of the starting materials. For example, the reactivity ratios between certain monomers can limit the amount of a hydrophilic monomer that can be copolymerized by radicálica route with hydrophobic monomers.

Although surfactants / emulsifiers do not reagents and colloidal stabilizers are very widely used, formulations prepared from these materials to Sometimes they have disadvantages. For example, these materials "Conventional" adsorb on the phase interface discontinuously simply through adhesive physical forces and, in certain circumstances, can be desorber resulting in an instability of colloids. The surfactants that can forming micelles can facilitate the transport of material from colloids to the continuous phase. This may not be desirable if the Transported material is able to change your physical state, by example by crystallization, in the continuous phase. The preparation of certain formulations such as microcapsules made by polymerization methods interfacial may require high levels of surfactant that they can adversely affect both the processing and the properties of the capsules. In addition, high levels of "free" surfactant can be removed by washing in the aqueous phase, which leads to environmental pollution not desired.

The above disadvantages can be avoided substantially if the surfactants bind chemical or irreversibly to the surface of the discontinuous phase.

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PVA).}

An example of this strategy is described in US Pat. 5,925,464. As described in said patent, polyvinyl alcohol (PVA) is used during the microencapsulation process, preferably one between a polyisocyanate and a polyamine, and reacts with the isocyanate to incorporate polyurethane groups into the walls of the microcapsules. This allows the surface active properties of the PVA to bind to the microcapsules and, as specified in the patent, "a uniform layer of water-soluble polymer is produced around each capsule" which should form a film upon drying. PCT application WO 98/03065 describes a similar concept using what is called "a non-micellar surfactant"

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It would be advantageous to provide surfactants that they can bind to the surface of said microcapsules or, alternatively, that can be linked to the emulsion drops, of such that the superficially active action is maintained relatively uniform throughout the resulting product or that is relatively available uniformly during the process of product preparation, for example, during the processes of microcapsule production.

In US 6,262,152 (Fryd et al.) describes a dispersion of particles such as pigments in a liquid vehicle in which the solid particle is insoluble, in the that the particles are trapped in a polymer matrix formed by crosslinking functional residues of a dispersant polymeric that has at least one soluble segment in the vehicle liquid and at least one insoluble segment in the liquid vehicle, in where said insoluble segment has the functional remains crosslinkable The grid or matrix of the surrounding crosslinked polymer each particle is formed by very stable crosslinking bonds that effectively prevent the particle from leaving the "core" formed by the polymer. The Examples show that a relatively high proportion of polymer to provide said polymeric matrix that surrounds and traps the particle.

Summary of the Invention

In accordance with the present invention, provides a process for the production of an emulsion oil-in-water comprising a liquid continuous phase and a liquid discontinuous phase, said being process defined in claim 1.

It should be understood that the expression "phase liquid discontinuous ", as used herein, includes a liquid discontinuous phase having a dispersed solid within it.

Emulsions made in accordance with the invention are particularly suitable for use in a process of microencapsulation.

A process for the production of microcapsules can understand:

(i) prepare an emulsion in which the phase discontinuous contains one or more monomers or prepolymers capable of form a microcapsule wall and one or more materials to encapsulate

(ii) form microcapsules by interfacial polymerization adjacent to the interface between the phase discontinuous and the continuous phase of the emulsion, where one or more of said monomers or prepolymers are reacted before and / or after preparation of the emulsion, with a stabilizer polymeric having a hydrophilic functional moiety and a moiety hydrophobic, and comprising a plurality of vinyl monomers, not being formed exclusively by vinyl esters or by their hydrolyzed products, of which at least some contain functional groups capable of undergoing reactions of nucleophilic crosslinking or condensation on the surface of the interface of the dispersed and continuous phases of the emulsion with said monomer or prepolymer.

Polymeric stabilizers for use in This invention contains two types of units: a) units hydrophobic, containing crosslinking functional moieties; and b) hydrophilic groups that provide colloidal and other stabilization  surface active properties. Stabilizers Polymers for use in this invention generally comprise two types, namely, random graft copolymers and copolymers of block.

Polymeric stabilizers for use in this invention are composed of a plurality of monomers Vinyl Some of them, as discussed below, they contain functional groups ("crosslinking groups") that are capable of undergoing a nucleophilic or condensation reaction with residues or groups present in a variety of materials such as wall forming monomers or prepolymers, or other materials contained in the liquid phase of an emulsion oil-in-water. (This is the opposite to certain prior art surfactants that have reactive functional groups that suffer root reactions, in nucleophilic or condensation site). The reactions mentioned above take place at the interface of the two phases of an emulsion (i.e. discontinuous and continuous phases, respectively). The reactions in question take place with compounds or polymers that dissolve in the liquid phase discontinuous

Detailed description of the invention

The invention involves the use of stabilizers reactive polymers. These polymeric stabilizers contain reactive or crosslinking groups that react with moieties functional of certain materials in such a way that they bind the surfactant to said materials. In one embodiment the materials in question they are generally organic monomers or resins or prepolymers that are used to prepare polymer microcapsules. Surfactants can definitely bind to the drops of the emulsion or the resulting microcapsules (or both). The reactive polymeric stabilizers of the present invention can be random graft copolymers or block copolymers. In in any case, they contain hydrophobic units that contain themselves same crosslinking groups, and also hydrophilic groups, which They provide stabilizing properties of the emulsion. The random graft copolymers have a "main chain" hydrophobic and hydrophilic "arms" while the block copolymers have hydrophobic and hydrophilic groups in which the hydrophilic group contains the crosslinking element.

Polymeric surfactants reactive for use in the present invention they may contain more than one type of monomer capable of undergoing a crosslinking reaction. For example, the copolymers may comprise monomers comprising functions amine and carboxylic acid, as in Examples 2e, 2f and 2g shown below. The copolymers can comprise monomers comprising hydroxyl and carboxylic acid functions such as in Example 1e shown below.

Polymeric stabilizers for use in this invention can be manufactured as is known in the art modifying polymers prepared previously or by production via polymerization in a single stage or in several stages.

Polymeric surfactants reactive for use in this invention, both random graft copolymers and block copolymers can be represented by the formula:

one

where Z is a group methoxy polyethylene glycol; R1, R and R2 are independently H or methyl; X is a hydrophilic functional moiety; L is a residue that contains a crosslinking group capable of suffering nucleophilic crosslinking or condensation reactions in the interface of the dispersed and continuous phases of said emulsion, in wherein said crosslinking group is selected from -OH; -NHA where A is hydrogen or C 1 -C 4 alkyl; and -COOH or a salt thereof; And it is a hydrophobic residue; the value of e goes from 0.005 to 0.33; the value of f ranges from 0.05 to 0.4; and the value of g goes from 0.10 to 0.90. If the surfactant is a graft copolymer randomly, the units e, f and g are distributed randomly, and if the surfactant is a block copolymer units f and g they are contained in a hydrophobic block and the units e are contained in a block hydrophilic

The expression "units e, f and g" such as used before indicates functional debris between square brackets that precede the subscripts e, f and g, respectively, of the previous formula. Each unit e, f and g derives from a monomer corresponding vinyl and, as indicated above, each type of unit e, f and g may comprise one or more different monomers. When R1, R and R2, respectively, are hydrogen, the monomer relevant is an acrylate or styryl monomer, and when R1, R and R2, respectively, are methyl, the relevant monomer is a methacrylate type monomer. Generally preferred methacrylate monomers. A styrene monomer (useful for example in unit e) has R1 as H and X as a derivative phenyl.

The values of e, f and g are determined essentially through the relationships of monomers that react to form units e, f and g, respectively.

The polymer will start with a hydrophilic group to derive from a hydrophilic initiator that has the formula II.

2

where A is a group such as bromine that under certain conditions, such as in the presence of a transition metal complex, can be activated in such a way that the vinyl monomer units are inserted into the bond of carbon-A, and Z is a group methoxy-polyethylene glycol. It should be noted that the group it has one or more units e when e is present in a copolymer of two blocks. The units e are distributed randomly in a type copolymer hair comb.

It is preferable that in formula (I):

(i) the group e is derived from one or more monomers that they are a methacrylate derivative (when R1 is methyl and the function derivative is -X) or an acrylate derivative (when R1 is hydrogen and the derivative function is -X) or is a derivative of styrene (when R1 is hydrogen and X is phenyl substituted with the hydrophilic moiety), in wherein said derivative carries a hydrophilic moiety selected from -SO 3 -, polyethylene glycol optionally protected in the C 1 -C 4 alkyl ends; -COOH or a get out of it; carboxybetaine; and sulfobetaine; an ammonium salt quaternary -N + R 3 C in which R 3 is H or alkyl C 1 -C 4 or -CH 2 CH 2 OH.

(ii) group f is derived from one or more monomers which are a derivative of methacrylate (when R is methyl and the function derivative is -L) or an acrylate derivative (when R is hydrogen and the derivative function is -L) or a styrene derivative (when R is hydrogen and L is phenyl substituted with the crosslinking group), in where said derivative carries a crosslinking group selected from -OH, which includes for example propylene glycol; -NBA where A is hydrogen or C 1 -C 4 alkyl; and -COOH or a get out of it; Y

(iii) group g is derived from one or more monomers which are a methacrylate derivative (when R2 is methyl and the derivative function is -Y) or an acrylate derivative (when R2 is hydrogen and the derivative function is -Y) or a styrene derivative (when R2 is hydrogen and Y is phenyl optionally substituted with a hydrophobic group) wherein said derivative is, or carries, a residue hydrophobic selected from -CO-O - (- Si (CH 3) 2 O -) n H where n goes from 3 to 20; -CO-O-propylene glycol; -CO-O-A where A is a group C 1 -C 12 alkyl, a cycloalkyl group, a alkylcycloalkyl group, an aralkyl group or a group alkylaryl; and -CONHB where B is an alkyl group C_ {5} -C_ {12}.

It is especially preferable that the unit e derives from one or more of the following monomers:

DMMAEA betaine *: acid 2- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) ethanoic acid, where R1 is methyl and -X has the formula

3

QuatDMAEMA: methacrylate salt 2- (trimethylammonium) ethyl;

where R1 is methyl and -X has the formula wherein Hal - is a suitable anion such as halide, by example iodide or chloride

4

DMMAPSA betaine: acid 3- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) propyl sulfonic acid, where R1 is methyl and -X has the formula

5

NaMAA *, the sodium salt of methacrylic acid, in where R1 is methyl and -X presents the formula

6

MAOES * mono-2- (methacryloxy) ethyl succinate in where R1 is methyl and -X presents the formula

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7

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PEGMA: mono-methoxy poly (ethylene glycol) mono-methacrylate; where R1 is methyl and -X has the formula in which n indicates the degree polymerization medium of the polyethylene glycol chain and that usually goes from 5 to 75

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8

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SSA: acid styrene-4-sulfonic;

where R1 is hydrogen and -X presents the formula

9

It is preferable that the unit derives from one or more of the following monomers:

EEA: 2-Aminoethyl methacrylate in where R is methyl and L is the group

10

HEMA: 2-Hydroxyethyl methacrylate, where R is methyl and L is the group

eleven

NaMAA * where R is methyl and L is the group

12

MAOES *: where R is methyl and L is the group

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13

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PPGMA *: mono-methacrylate poly (propylene glycol), where R is methyl and L is the group in which n indicates the degree of polymerization of polypropylene glycol and preferably ranges from 5 to 50

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14

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It is preferable that the unit g derives from one or more of the following monomers:

methyl methacrylate, where R is methyl and Y It is the group:

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fifteen

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PDMSMA: mono-methacrylate poly (dimethylsiloxane), typically with a molecular weight mean of 1000, where R is methyl and Y is the group

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16

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PPGMA *: mono-methacrylate poly (propylene glycol), where R is methyl and L is the group in which n indicates the degree of polymerization of polypropylene glycol and preferably ranges from 5 to 50. In general, it is preferable a longer chain length in order to provide the hydrophobic character necessary.

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17

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It should be noted that certain monomers (marked with an asterisk) exist in more than one group and, for example, they have hydrophilic groups X that can be used, if want to provide crosslinked (that is, they can also act  as rest L). For example, acid salts can be used carboxylic to stabilize, when monomers are incorporated that they carry -CO2 X groups in the hydrophilic part of the surfactant. However, free carboxylic acids can be used for crosslinked, using the chemistry of azidirine or carbodiimide, when there are monomers that carry -CO2H groups incorporated into the part hydrophobic surfactant. Obviously, if -CO2H is used for crosslinking it cannot be used for stabilization. When two different groups of the surfactant are able to react in crosslinking reactions, but have a very reactivity different, it is possible to use the least reactive group for stabilization of, for example, carboxylates of the sections hydrophilic and hydroxyl in the hydrophobic sections. The specialist in the art he is able to easily select the conditions in which a given group gives rise to crosslinking reaction, or alternative conditions so that it does not.

Other additional examples of monomers that can be used to form the "e" unit (and provide the corresponding values of R1 and X) include chloride 4-vinylbenzyl trimethyl ammonium, the 2-N-morpholinoethyl, methacrylate of 2-methacryloxyethylphosphonate, the acid 2-acrylamido-2-methylpropane sulfonic

Other examples of monomers that can be used to form the unit "f" (and provide the corresponding R and L values) include 2-methoxy vinylphenol alcohol 4-vinylbenzyl, 4-vinylphenol, 2,6-dihydroxymethyl-4-methoxystyrene, 3,5-dimethoxy-4-hydroxystyrene, chloride 2-hydroxy-3-methacryloxypropyl trimethyl ammonium methacrylate 3-chloro-2-hydroxypropyl, 3-hydroxypropyl methacrylate, methacrylate 2-hydroxy-3-phenoxypropyl, diethylene glycol mono-methacrylate, methacrylate 2,3-dihydroxypropyl glycoside of 2-methacryloxyethyl, sorbitol methacrylate, 2-methacryloxyethyl ester of caprolactone, 4-hydroxybutyl methacrylate, methacrylate 2-hydroxypropyl, 4-amino styrene, 2- (iso-propylamino) ethylstyrene, acid 4-N- (vinylbenzyl) aminobutyric acid, hydrochloride from 3- (N-Styrylmethyl-2-aminoethylamino) -propyltrimethoxysilane, N- (3-methacryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, 4-vinylbenzoic acid, acid 4 - ((3-methacryloxy) propoxy) benzoic, mono- (2- (methacryloxy) ethyl) phthalate.

Other examples of monomers that can be used to form the unit "g" (and provide the corresponding R 2 and Y) values include acrylate derivatives (R 2 = H) or methacrylate (R2 = methyl) in which Y is COOR, and R is alkyl, cycloalkyl, aralkyl or alkaryl, or poly (dimethylsiloxane), vinyl esters, vinylhalogens, styrene or styrenes optionally substituted.

As indicated above, the Formula (I) describes graft copolymer stabilizers randomized and block copolymers. The stabilizers of random graft copolymers useful in this invention have a main hydrophobic chain and hydrophilic "arms". TO Below is a typical structure presented without the hydrophilic group, which includes a polymethyl main chain methacrylate containing methacrylate of methoxy-polyethylene glycol and methacrylate functions of hydroxyethyl. This structure is illustrated as Formula III.

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18

In this structure, Z is a hydrophilic group such as methoxy-PEG in which PEG (polyethylene glycol) indicates a number of units of ethylene oxide (C 2 H 4 O) q. Alternatively Z may be derived from a monomer that is another (meth) acrylate ester or a functionalized (meth) acrylamide derivative containing a hydrophilic group such as a sulfonate, for example 2-acrylamido-2-methylpropane sulfonic acid. Group mixtures can also be used.
Z.

L in the above structure is a crosslinking group such as -CO 2 CH 2 CH 2 OH, in the hydroxyethyl monomer
(met) acrylate (where R = H or Me). Alternatively, L may be derived from a monomer that is another (meth) acrylate ester or functionalized (meth) acrylamide derivative containing a crosslinking group such as that found in N- (2-hydroxylpropyl) methacrylamide or a derivative of substituted styryl containing a crosslinking group such as SH or OH or NHA, wherein A is hydrogen or C 1 -C 4 alkyl, represented by the structure -C 6 H 4 -CH 2 NH2.

The values of m range between about 0.05 and 0.35 and preferably between 0.05 and 0.30, the values of n range between 0.13 and 0.90 and preferably between 0.50 and 0.80, and p values range between 0.02 and 0.20. The polymers are random graft copolymers (comb) because the units indicated as m , n and p can be distributed in any order in the chain of the molecule. It should be noted that the -CO-Z residues form the hydrophilic "arms" of the random graft copolymers, and the remaining units form the hydrophobic main chain that also contains the crosslinking moieties L.

It should be noted that formula (III) is a form more specific to Formula (I) except for the end group, and that the monomers listed above with respect to formula (I), where -X has a carboxyl structure, they can be used to provide the relevant group -CO-Z of the formula (III).

In general, random graft copolymers for use in this invention can be prepared by Typical known methods of surfactant preparation copolymers of random graft or similar materials. These methods include (a) monomer graft polymerization hydrophilic to a hydrophobic main chain, or (b) the process inverse to (a), or (c) the chemical conversion of suitable monomers which have been copolymerized with main chain monomers hydrophobic Polymers with properties can be manufactured surfactants similar to those of graft copolymers can by random copolymerization of hydrophilic monomers and hydrophobic

The preferred method of preparation for any graft copolymers or similar given will depend on the nature and properties of the starting materials. By For example, the reactivity ratios between certain monomers can limit the amount of a hydrophilic monomer that can copolymerize by radical route with hydrophobic monomers of main chain

PCT application WO 96/00251 shows some new amphipathic graft copolymers and new methods of preparation.

The preferred block copolymers for use in the present invention they are composed of a block A hydrophilic, which in turn is composed of a hydrophilic and / or a hydrophilic monomer (s) (-CH 2 CR 1 X-), that is, it is attached to a hydrophobic B block that is composed of copolymerized hydrophobic monomer (s) (-CH 2 CR 2 Y-) and crosslinking units (-CH 2 CH 2 CRL-). These are represented as Formula IV, which It is a more specific version of formula (I).

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19

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The hydrophilic block A may be constituted by one or more monomers that give rise, after polymerization and optionally undergo some additional chemical modification, to water soluble polymers. The group designated "hydrophilic" in Formula (IV) has the same meaning as provided before with respect to Formula (I). The monomers may be no ionic or they may be positively or negatively charged but, as part of the surfactant composition should not react with the oil wall forming materials with which they leave to use the surfactants.

In the previous Formula IV, the values corresponding to units a and b range between about 0.3 and about 0.7, and the corresponding values ac and range between about 0.05 and about 0.35, and preferably between about 0.05 and about 0.25 and between about 0.75 and about 0.95, respectively. Preferably, the value of c is selected such that it balances the hydrophobicity of the surfactant with the reactivity of the crosslinking group; a preferred range for c is between about 0.1 and 0.25. Units c and d (ie, the unit in square brackets before subscripts c and d respectively) comprise the hydrophobic main chain of block copolymer surfactants and are derived, for example, from acrylate or methacrylate or styryl structures. The unit d, for example, can be a derivative of acrylate (R 2 = H) or methacrylate (R 2 = methyl) where Y is COOR, and R is alkyl, cycloalkyl, aralkyl or alkaryl. The choice of Y determines the hydrophobicity of this surfactant unit. For example, if Y is CO 2 C 8 H 17 and R 2 is hydrogen or methyl, this unit of the surfactant will be very hydrophobic. If, on the other hand, Y is COOCH 3 and R 2 is hydrogen, the unit is less hydrophobic. If d is a styryl unit (i.e., Y is phenyl and R2 is hydrogen) the unit will be very hydrophobic.

Group c contains crosslinking groups in the remainder L and branching groups R (which are usually hydrogen or methyl). The crosslinking groups of the moiety L are preferably functional groups of esters that are capable of reacting with the wall-forming agents used in the production of microcapsules such as isocyanates. The crosslinking groups L preferably terminate in reactive groups such as -OH, -SH, -CO 2 H or -NHA wherein A is hydrogen or C 1 -C 4 alkyl. Preferred c units include those derived from the hydroxyethyl methacrylate monomers (R = methyl, L = COOCH2CH2OH), methacrylic acid (R = methyl, L = -CO2H), (mono- 2- (methacryloxy) ethyl succinate (R = methyl, L = COOCH 2 CH 2 OCOCH 2 CH 2 -CO 2 H), or 2-aminoethyl methacrylate (R = methyl, L = COOCH 2 CH 2 NH 2).

The hydrophilic units comprising block a are preferably methacrylate structures and the hydrophilic is a group such as methoxy-PEG. The group X is preferably a hydrophilic moiety such as that of 2- (trimethylammonium) ethyl methacrylate iodide, 2- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) ethanoic acid, 3- (N, N -dimethyl-N- (2-methacryloxyethyl) ammonium) propyl sulfonic acid or styrene-4-sulfonic acid or 2-acrylamido-2-methylpropane sulfonic acid (AMPS).

Examples of water-soluble nonionic polymers suitable for use in block a include, but are not limited to, poly (ethylene oxide) ("PEO"), poly (acrylamide), poly (vinyl pyrrolidone) ("PVP"), poly (methyl vinyl ether). PEO and PVP cannot be used in formulations containing polyacids that complex with their functional groups. The polymers can have linear or comb structures. Polymers such as polyethoxy (meth) acrylate, polyvinyl alcohol, poly (ethylene imine) and polyvinyl amine contain reactive groups that would react with isocyanates such as those used in polyurea microencapsulation processes, and are not preferred for block construction a .

Examples of negatively charged monomers which can be included in these polymers include, among others, those made from (salts of) acrylic acid, acid methacrylic, beta-carboxyethyl acrylic acid, mono-2- (methacryloxy) ethyl succinate, 4-vinylbenzoic acid, itaconic acid, vinyl acid sulfonic acid, 2-sulfoethyl methacrylate, acid 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and 4-styrene sulfonic acid. Note that it is not preferable to use polyacrylic acid in combination with main chains of methoxy-PEG since it It will produce an association between them. However, the acid (meta) acrylic could be used as a component of hydrophobic sections of these surfactants as it would be present in comparatively smaller amounts.

Examples of negatively charged monomers which can be included in these polymers include, among others, those made from diallyldimethyl ammonium salts, quaternary salts of dimethylaminoethyl methacrylate (DMAEMA) and of dimethylaminoethyl acrylate.

The hydrophobic block B can be obtained from of one or more monomers that polymerize give rise to a polymer insoluble in water that can be strongly adsorbed to the surface of the discontinuous phase. Examples of suitable monomers include, among others, acrylate esters, methacrylate esters, vinyl esters, vinyl halogens, styrene or styrenes optionally substituted.

The crosslinking units can be co-polymerized in a desired molar ratio with with respect to the monomers of the hydrophobic block B. The relationships typical vary between two and ten units of hydrophobic monomer in front of a crosslinking unit. The relationship chosen depends on the molecular and balance weights hydrophilic-hydrophobic hydrophobic units and crosslinkers. The structure of crosslinking agents depends of the crosslinking chemistry between the surfactant and the components contained within or on the discontinuous phase.

The crosslinking group of the polymeric surfactant reagent reacts with a substance dissolved in the liquid phase discontinuous (reaction couple). In the production process of microcapsules, the reaction partner will be the monomer or prepolymer that will form the wall of the microcapsule. However, a Emulsion manufactured in accordance with the present invention can involve a larger range of dissolved reaction partners in the discontinuous liquid phase and able to react with the group crosslinker of the reactive polymeric surfactant.

Many types of chemistry are known from crosslinked For example, when the functional crosslinking moiety L ends in a hydroxyl or thiol reactive group, the pairs of Suitable reaction may present as reactive group corresponding, for example, an isocyanate, an ester or an epoxide. When the functional crosslinking moiety L ends in a group amino reagent, suitable reaction partners may present as the corresponding reactive group, for example, an isocyanate, a acetoacetoxy, an aldehyde, an acrylate, a vinyl sulfone and a epoxide When the functional crosslinking moiety L ends in a acid reactive group, suitable reaction partners can present as a corresponding reactive group, for example, a isocyanate, an aziridine and a carbodiimide. Combinations Preferred crosslinker / couple of this invention include hydroxyl isocyanate, amine isocyanate and Carbodiimide acid.

The crosslinking group or groups may react with one or more reaction partners contained in the phase discontinuous The reaction partner may contain more than one type of functional group, capable of reacting with crosslinking groups reagents of the polymeric surfactant. The discontinuous phase too may contain substances that do not react with groups surfactant crosslinkers but which are capable of lead to interfacial polymerization.

The relationship of (a) the reaction partner dissolved in the discontinuous liquid phase and undergoing a reaction interfacial with (b) the rest of the phase components discontinuous determines the nature of the interfacial structure resulting. At one end, the structure can be a framework of inconsistent polymer that maintains phase integrity discontinuous formulation but not a barrier when it separates from the continuous phase. In this case, after spraying and dry, the components of the discontinuous phase are released immediately. At the other end, the structure can provide a robust and substantial barrier such as that of microcapsules that slowly releases phase components discontinuous when the formulation is sprayed and dried. The Barrier effectiveness is a function of a number of factors that include the thickness of the barrier, the particle size, the gradient of concentrations of the substance from the inside to outside of the capsule and the permeability of the substance through of the barrier. Those skilled in the art will appreciate that the Barrier effectiveness can be modified widely by varying these parameters. The nature of the interfacial material and the degree of crosslinking has a very significant effect. In general, however, the following indications indicate structures General Interfacials In ratios of approximately 3% p / p e lower structure (wall) interfacial with the phase discontinuous, poor and physical barriers are generally obtained weak. In ratios of approximately 8% w / w and above, They can get substantial barriers. The stable emulsions of This invention is typically made with 4% w / w and less than interfacial material with the discontinuous phase. The microcapsules of This invention is typically made with 10% w / w material. Interfacial with the discontinuous phase.

The functionality of the substance dissolved in the discontinuous phase, and capable of reacting with the cross-linking groups of the surfactant, suitably is equal to or greater than two. The invention is not limited by the structure of the substance as long as the substance is easily soluble in the discontinuous phase and reacts with the groups.
crosslinkers

Thus, for example, when the discontinuous phase contains isocyanates, the crosslinking groups contain one or more functional groups capable of reacting with isocyanate. These groups can be, for example, amino, hydroxyl, thiol or carboxyl (substituted). Hydroxyl and amino groups are preferred. The most suitable are the primary and secondary amino groups. Tertiary amino groups can catalyze isocyanate reactions but usually do not form stable reaction products. When more than one functional group X is present, the groups may be the same or different. Reactions with isocyanates are illustrated herein using structures.
generic.

Carboxylic groups can be introduced using, for example, mono-2- (methacryloxy) ethyl succinate, acrylic acid, methacrylic acid, acid beta-carboxyethyl acrylic acid 4-vinylbenzoic acid and itaconic acid. Can be achieved an improved adsorption to the oil-water interface forming the emulsion at a pH above the acid pKa, it is say, in salt form, which favors water solubility, and to then reducing the pH to below the acid pKa, which which will reduce water solubility.

The carboxylic acids react with isocyanates to form mixed anhydrides that quickly eliminate Carbon dioxide with the formation of carboxylic amides:

RNCO \ + \ R 1 CO 2 H → [RNHCOOCOR 1]? R 1 CONHR \ + \ CO 2

Hydroxyl groups can be introduced using hydroxyethyl methacrylate, N- (2-hydroxypropyl) methacrylamide or poly (ethylene glycol) n monoethacrylate. Can be introduce amino groups using hydrochloride of 2-aminoethyl methacrylate hydrochloride N- (3-aminopropyl) methacrylamide or methacrylate of 2- (tert-butylamino) ethyl. Thiol groups,  hydroxyl and amino react with isocyanates to form, respectively, thiocarbamate, urethane and urea bonds:

link thiocarbamate RNCO \ + \ R1 SH \ rightarrow RNHCO-S-R1 {} \ 0.05cm

link urethane RNCO \ + \ R 1 H → RNHCO-O-R1 {} \ hskip0.16cm

link ureaRNCO \ + \ R1 NH \ rightarrow RNHCO-N-R1

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The nature of crosslinking groups may be altered, or crosslinking groups can be introduced by a post-reaction of the copolymer. For example, the carboxylic groups can be imitated to make combs of polyimine

-CO_ {2} H \ + \ ethyleneimine \ rightarrow -CO 2 - [CH 2 CH 2 NH] n -H

The amino groups react with isocyanates of mode described above.

The reactivity of the functional group with the Isocyanate influences the rate at which the surfactant binds to the reagents in / on the discontinuous phase. For example, normally isocyanates react much faster than amines with alcohols or acids.

The polymeric surfactant may contain a crosslinking unit capable of reacting with an agent of coupling that is contained within the discontinuous phase of oil or that is added through the aqueous phase after the emulsion formation oil-in-water, and where the agent added is also able to react with isocyanate in the phase oil. This approach requires that the reactive surfactant be irreversibly link to the oil interface before the coupling agent addition.

Multifunctional aziridines such as CX-100, available in Avecia NeoResins (formula structural shown below, m = 3), can be used as agent coupling when acidic monomers are incorporated into polymeric surfactant. Aziridines react with isocyanates and with carboxy groups in the free acid form, but not in the form of salt.

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twenty

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Poly (carbodiimides) such as CX-300, available at Avecia NeoResins, can be used as a coupling agent when acidic monomers are used as crosslinking groups. Conventionally it is believed that the reaction between acid and carbodiimide results in three types of products as illustrated below. The products of N-acyl urea and urea are stable while the Anhydride can be hydrolyzed to give two carboxylic acids.

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twenty-one

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Block copolymers can be prepared by the methods commonly used today for Preparation of such materials. These tend to involve a live anionic polymerization or transfer polymerization of group. The preparation conditions for these methods are very demanding, for example, need for low temperatures, use of rigorously anhydrous solvents and extremely reagent cigars Additionally, the use of functional monomers requires often the use of chemistry of protective groups.

Recently, the appearance of a new procedure, radical transfer polymerization atomic (ATRP) polymerisation ") provides a system that allows control about the composition and length of the block. This method is tolerant with respect to the type of monomer [styrene and derivatives (met) -acrylics], to purity, to the presence of water, and often the use of functional monomers does not require protection / deprotection chemistry.

A system for carrying out the ATRP is described by Coca et al. in J Polym Sci: Part A Polym Chem , Vol. 36,1417-1424 (1998). The ATRP uses a Cu (I) halide, which reacts with ligands (often bidentate) to form a "CuX / 2L" complex. Halogenated initiators are used for polymerization. The Cu (I) complex reversibly activates latent polymer chains (and the initiator) by transferring the halogen end groups as shown in Scheme 1.

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Scheme one

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22

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In the case of some of the above block copolymers, hydrophilic block A can be introduced from a macro-initiator of defined structure [typically Z-OCOCMe_ {2} Br] that extends with appropriate amounts of hydrophobic monomers (CH2 = CR2Y) and crosslinkers (CH2 = CRL). Alternatively, or in addition to the above, the initiator (which may not be a macro-initiator) you can extend your chain with a hydrophilic monomer (CH2 = CR1X) to generate the block A and therefore with appropriate amounts of monomers hydrophobic (CH2 = CR2Y) and crosslinkers (CH2 = CRL) to generate block B (or alternatively groups CH 2 = CR 1 X, CH 2 = CR 2 Y, and CH 2 = CRL can be randomly copolymerized to form copolymers of graft).

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2. 3

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Hydrophilic residue [Z-OCOCMe 2 -CH 2 CR 1 X-] it can have Z as a C 1 -C 3 alkyl or a Methoxy-PEG group.

The vinyl monomers (CH2 = CR1X) that make up the hydrophilic unit (s) can be single or mixed monomers selected from, among others, methoxy-PEG- (meth) acrylate, acrylamide, vinyl pyrrolidone, sulfoethyl methacrylate, acid 2-acrylamido-2-methylpropane sulfonic acid, 4-styrene sulfonic acid, salts quaternary dimethylaminoethyl methacrylate (DMAEMA) and dimethylaminoethyl acrylate or DMAEMA at acidic pHs. Monomers Preferred include methacrylate iodide of 2- (trimethylammonium) ethyl, acid 2- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) ethanoic acid,  acid 3- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) propyl sulfonic acid styrene-4-sulfonic.

The hydrophobic block - [CH 2 CYR 2] - may be composed of single or mixed monomers selected from the above list. The crosslinking unit (s) - [CH 2 CLR] - can be single or mixed monomers selected from the above list. The optimal total molecular weight and optimal block sizes of the surfactants will depend on the nature of the monomers and the active ingredient used in the process. Molecular weights will generally range between about 1,000 and about 20,000. Preferred molecular weights are between about 5,000 and about 20,000. The crosslinking groups are incorporated at a level below 100% to the surfactant, preferably between about 2 and about 20 mole% of the hydrophobic block b . The nature of the polymeric surfactant will determine the medium in which it can be manufactured and used. This will vary between non-polar solvents such as xylene and polar solvents such as water. Although surfactants that have some solubility both in the discontinuous phase and in the continuous phase are suitable for use in this invention, surfactants that have limited solubility within the continuous phase and that are strongly adsorbed in the continuous phase are preferred. interphase of the discontinuous phase. The hydrophobic monomers described above as CH2 = CRY units adhere strongly in general to the discontinuous phase. Methyl methacrylate is adequately hydrophobic, while butyl acylate and styrene are even more
hydrophobic

Polymers provide the introduction of controlled structures that have advantages. Polymers obtained by controlled root polymerization they generally have lower polydispersities than other polymers  Comparable obtained by conventional root methods. Therefore, the control minimizes the amount of tail weight low molecular The adsorption force of the surfactants to an aqueous discontinuous phase depends on the number of units hydrophobic surfactant that are available for adsorption. Assuming a comparable composition in the range of molecular weights, the chains of greater molecular weight will have relatively more hydrophobic units and will tend to join more strongly than low molecular weight chains. In this way, for the minimum effective ratio of surfactant to phase discontinuous, the amount of "unbound" material is minimized In the continuous phase. Thus, the material that is minimized or eliminated could act as a vehicle for the phenomenon of "Ostwald ripening ". This methodology provides several benefits: (1) The bound surfactant will be difficult to physically separate from the interphase of the discontinuous phase, specifically a drop of liquid emulsion or the surface of a microcapsule particle. This greatly improves the effectiveness of the action of the surfactant and It allows the preparation of robust formulations. (2) A charge selected in the surfactant polymer can be linked to the interphase of the discontinuous phase. This allows you to continue with the elaboration, for example, the use of the load to control the heterofloculation (3) Appropriate functional groups loaded, or inside the bound surfactant, they could react with a monomer, oligomer or polymer added through the continuous phase. Of this mode could introduce a barrier coating in the phase individual that could be a drop of liquid emulsion or a particle such as a microcapsule.

Therefore, when preparing stable or microcapsule emulsions by the processes mentioned above, the polymer is preferably somewhat soluble or dispersible in the continuous phase, which in most cases is the aqueous phase. In such processes, the oil used for microencapsulation applications contains the material to be encapsulated and the wall-forming material (s) are dispersed in water using the reactive polymers of the present invention. For emulsion applications, the substance capable of reacting with the crosslinking groups will be similarly contained in the oil phase, which will generally also contain an active ingredient such as an agrochemical active ingredient that may be dissolved or dispersed in the liquid oil phase. Therefore, the surfactant is in intimate contact with the oil interface. The reactive groups of the surfactant are induced to react with the substance (s) capable of reacting with the crosslinking groups of the surfactant. When these materials are wall-forming they can be polymerized simultaneously or sequentially to form the wall of the
microcapsule

The polymers can be used as surfactants and / or as protective colloids in interfacial polymerization processes to form stable emulsions or microcapsules causing polymerization / and reaction in some cases) of the ingredients contained in the emulsion. In one type of interfacial polymerization or condensation process, monomers of the aqueous and oil phases are brought into contact at the oil / water interface, where they react by condensation to form the microcapsule wall. This is described, for example, in US Pat. No. 4,280,833. In another type of polymerization reaction, generally called in situ interfacial condensation, all wall-forming monomers or prepolymers are contained in the discontinuous phase. This is then dispersed in a continuous phase that contains the surface activations. Normally in these cases the discontinuous phase is an organic or oleaginous phase and the continuous phase is an aqueous phase. However, the formation of water / oil emulsions is not uncommon in this type of microencapsulation process, in any case, the discontinuous phase is dispersed in the form of discrete drops through the continuous phase by means of an emulsion. An interface is formed between the two phases. By heating the emulsion and controlling the pH, in situ condensation of the wall-forming materials and the maturation of the polymers at the interface can be initiated. The surfactants for use in this invention will react with the wall forming materials before or during the polymerization step. The result is a suspension of microcapsules in the continuous phase in which the microcapsules have surfactants of the present invention bound through crosslinking groups.

In addition to the use in microencapsulation processes, the surfactants for use in this invention are suitable for stabilization of the emulsion. It is well known in the art that desorption of the surfactant from an interface can lead to the destabilization of an emulsion. In addition, it is known that the effects of micelization also lead to the redistribution of components throughout the system, which can lead to the phenomenon of "Ostwald ripening" and other unwanted interactions. Incorporation into the discontinuous phase (usually the oil phase) of a small amount of material that is capable of reacting with the polymeric surfactants of the present invention may result in stabilization of the emulsion. The reaction of this small amount of material in the discontinuous phase with the surfactants used in this invention results in emulsion compositions having the surfactants of the invention bound at the interface. An advantage provided by said emulsions is a reduction or elimination of foaming due to reduced or zero levels of free surfactant. Other advantages may come from better control of droplet size and better long-term stability.
term.

The invention is illustrated by the following Examples in which all parts and percentages are expressed by weight, unless otherwise indicated. The following are used Abbreviations:

AEMA.HCl: Hydrochloride 2-aminoethyl methacrylate; from Sigma Aldrich.

BMA: n-Butyl methacrylate; from Sigma Aldrich.

CX-300: Crosslinker poly (carbodiimide); from Avecia NeoResins.

DETA: Dietilen triamine of Sigma-Aldrich

DMAEMA: Methacrylate 2- (dimethylamino) ethyl; from Sigma Aldrich.

QuatDMAEMA (PP): Iodide or methacrylate chloride of 2- (trimethylammonium) ethyl where PP indicates that the monomer used was DMAEMA and the quaternization reaction was carried out using methyl iodide.

DMMAEA betaine: 2- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) ethanoic acid prepared by a modification of the procedure presented in literature; LA Mkrtchyan et al. Vysokomol Soedin., Ser. B 1977, 19 (3) , 214-16.

DMMAPSA betaine: Acid 3- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) propyl sulfonic; from Sigma Aldrich.

HDIT: Trimer of hexane-1,6-diisocyanate biuret; Desmodur N3300 from Bayer.

REMA: Methacrylate 2-hydroxyethyl; from Sigma Aldrich.

NaMAA: Sodium salt of methacrylic acid; from Sigma Aldrich

MAOES: Succinate of mono-2- (methacryloxy) ethyl; from Polysciences Inc.

MMA: Methyl methacrylate; from Sigma Aldrich.

PEGMA (#): Mono-methoxy poly (ethylene glycol) mono-methacrylate where # is the average degree of polymerization of the PEG chain; from Polysciences Inc. or Laporte Performance Chemicals.

PCDI: Poly (carbodiimides); from Sigma-Aldrich

PDMSMA: Poly (dimethylsiloxane) mono-methacrylate with an average molecular weight of 1000

PMPPI: Poly (Methylene) poly (phenylene isocyanate); Suprasec 5025 of Huntsman.

PPGMA (#): poly (propylene glycol) mono-methacrylate, where (#) is the average grade of polymerization of the PPG chain; from Polysciences Inc. or from Laporte Performance Chemicals.

SSA: acid styrene-4-sulfonic; from Sigma Aldrich

TDI: Tolylene diisocyanate (mixture of isomers); from Sigma Aldrich.

Atlas G5000: Copolymer of poly (oxide of ethylene-block-propylene oxide); from Uniqema.

GL05: Poly (vinyl alcohol); Gohsenol of Nippon Gohsei.

LIC 0.1: Alkylated polyfructose surfactant; from Inutec.

Span 80: Sorbitan oleate ester; from Uniqema.

Morwet D425: Sodium salt of a polymer of condensation of sulfonated naphthalene-urea; from Witco

Solvesso 200: Alkylated naphthalene solvent; from Exxon-Mobile.

s-Metolachlor: (S) 2-Chloro-6'-ethyl-N- (2-methoxy-l-methyl ethyl) acet-o-toluidide.

Fenpropidine: (RS) -l- [3- (4-tert-Butylphenyl) -2-methylpropyl] piperidine.

λ-Cyhalotrin: (RS) - α-cyano (3-phenoxybenzyl) (Z) - (1R) -cis-3- (2-chloro-3,3,3-trifluoropropenyl) -2,2-dimethyl cyclopropane carboxylate.

Teflutrin: 2,3,5,6-Tetrafluoro-4-methylbenzyl (Z) - (1 RS) -cis-3- (2-chloro-3,3,3-trifiuoroprop-1-enil) 2,2-dimethyl cyclopropane carboxylate. Sigma Aldrich, Gillingham, R.U. Polysciences Inc, Warrington, PA 18976, USA Laporte Performance Chemicals, Hythe, R.U. Bayer, Leverkusen, Germany. Avecia NeoResins, Waalwijk, The Netherlands. Exxon-Mobile, Houston, USA Witco (Crompton Europe), Slough, USA Uniqema Crop Protection, Gouda, The Netherlands. Nippon Gohsei, Osaka, Japan.

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For clarity, the structures of Previous monomers are presented as:

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Example one

Synthesis of reactive polymeric surfactants by radical atomic transfer polymerization (ATRP) General synthetic procedure

In a typical polymerization, the monomers were dissolved in the molar relationships required in a solvent or mixture of suitable solvents. Normally used toluene for reactions in which all components were soluble in toluene. Methanol-water mixtures were used (between 1: 1 and 3: 1 v / v) for mixtures of components such as AEMA.HCl, QuatDMAEMA, SSA, DMMAPSA betaine and DMMAEA betaine, which They are poorly soluble in organic solvents.

An appropriate initiator was added. For the preparation of non-ionic block co-polymers, this was a polymeric macroinitiator such as mono-2-bromoisobutyryl mono-methoxy poly (ethylene glycol), abbreviated PEG-Br (#), where # is the number of units of ethylene glycol, prepared by a method described in literature (Jankova et al . Macromolecules, 1998, 31 , 538-541). For the preparation of graft copolymers or ionic block copolymers, the initiator was a monomeric 2-bromoisobutyryl ester, which may be ethyl-2-bromoisobutyrate (EtBiB) or a different monomeric 2-bromoisobutyryl ester (BiB-R) . The amount of initiator added was dependent on the molecular weight set as the target for the co-polymer and was calculated from the ratio:

(Moles \ of \ monomer) / (Moles \ of \ initiator) = \ text {Degree of polymerization of the copolymer

A ligand was also added for in-situ formation of the copper complex. Normally, this was 2,2'-bipyridine (BPY) for polymerizations in mixtures of methanol / water and Nn-propyl-2-pyridylmethaneimine (PPMA), prepared by the method described in literature (Haddleton et al ., Macromolecules, 1997, 30 , 2190-2193), for polymerizations in toluene.

The solution was deoxygenated by passing dry nitrogen for 15-30 minutes before Addition to a Schlenk tube, preloaded with copper salt (I) appropriate to form the complex to act, and to It was then charged with nitrogen. Normally, bromide of copper (I), but sometimes it was copper (I) chloride. Chloride was used copper (I) when a higher polymerization rate was required. The reaction was carried out under a nitrogen atmosphere at a controlled temperature that ranged between 25 and 90 ° C for between 3 and 24 hours. The progress of the reaction was measured by 1 H NMR spectroscopy. In the case of copolymers of Ionic block was added a second monomer or a mixture of co-monomers to form the second block when the Lot conversion of the first monomer exceeded 80%. To the end, when the tube opened to the atmosphere the reaction stopped and The polymer solution was purified by one of several techniques:

(i)

For a reaction carried out in toluene was diluted the solution of polymer with more toluene, cooled and filtered to remove the insoluble material. At that time, the polymer solution was optionally passed through a small oxide column of activated basic aluminum before collecting the product by Selective precipitation in hexane and dry under vacuum at 20 ° C and 70 ° C.

(ii)

For a reaction carried out in a mixture of methanol / water the solvents were separated by freeze drying or rotary evaporation. TO then, the polymer was dissolved in toluene, THF or dichloromethane and filtered to remove insoluble material before that the product be isolated by selective precipitation in hexane and dry it under vacuum at 20 ° C to 70 ° C.

(iii)

For a reaction that requires quaternization of DMAEMA post-polymerization is diluted the reaction solution with toluene, cooled and filtered to remove insoluble material, then the solvent in vacuo. The polymer was dissolved in THF and a 20% molar excess of iodomethane to tertiary amino groups in dry nitrogen atmosphere. The solution was stirred under an atmosphere of nitrogen at 20 ° C for between 16 and 20 hours before isolating the polymer by selective precipitation in hexane. So he polymer was purified by Soxhlet extraction with hexane for 24 hours followed by vacuum drying at 50 ° C.

The previous general procedure was used to prepare the polymeric surfactants detailed in Table 1, in which:

Examples 1a to 1g illustrate copolymers of hydroxyl and hydroxyl plus carboxylic comb.

Examples 2a to 2i illustrate copolymers of Amine and amine plus carboxylic comb.

Examples 3a to 3c illustrate copolymers of carboxylic comb.

Examples 4a to 4d illustrate copolymers of block containing hydroxyls.

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26

27

28

29

30

31

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In Table 1, column 2 ("Structure"), the Detail is as follows:

(i) Non-ionic diblock refers to a AB block copolymer in which a block is mono-methoxy poly (ethylene glycol) and the second block is a methacrylic co-polymer that they contain the latent reactive groups;

(ii) Non-ionic comb refers to a comb co-polymer in which the chains sides are mono-methoxy poly (ethylene glycol) and the main chain is a co-polymer of methacrylic containing the latent reactive groups;

(iii) anionic / non-ionic, cationic / non-comb ionic and hybrid / nonionic ion refers to copolymers type comb in which the side chains are mono-methoxy poly (ethylene glycol) and main chains are methacrylics containing reactive groups latent and monomer units that are anionic, cationic or Hybrid ion at the pH of relevance.

It should be noted that in Example 4d it was added DMAEMA to grow the second block after the first co-monomer mixture would have reached a high conversion, and tertiary amine groups were subsequently quaternized with methyl iodide.

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Examples 5th-61

The following examples serve to demonstrate that the reactive polymeric surfactants can be crosslinked at an oil / water interface using isocyanates and carbodiimides to prepare stable emulsions.

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Examples 5a-5k

Isocyanate method

Reactive polymeric surfactants were used containing amino groups to emulsify an immiscible phase in water containing a small amount of an isocyanate multifunctional hydrophobic such as PMPPI or HDIT. When it was necessary, the emulsion was adjusted to pH 7-9 and to then stirred for 1-24 hours between 20 ° C and 50 ° C for crosslinking to occur.

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Examples 6a-6l

Carbodiimide method

Reactive polymeric surfactants were used containing carboxylic acid groups, above pH 7, to emulsify a water immiscible phase that contains a small amount of a multifunctional carbodiirnide such as CX-300 or PCDI. The emulsion was adjusted to pH <3 and stirred for 1-24 hours at 20 ° C so that it produced the reticulate.

Emulsification was carried out using a rotor-stator high shear mixer like those manufactured by Silverson and Ystral. The drop size of the emulsion did not vary significantly during the reaction of crosslinked Using an optical microscope, the surface texture of the emulsion drops, some of the which had ceased to be spherical. Depending on the quantities  of used crosslinker and of the reactive polymeric surfactant the Most emulsion drops coalesced during drying in a manner similar to that of the emulsion prepared without surfactants crosslinked Details are shown in Table 2.

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Example 7

Examples 7 and 8 illustrate that emulsions using crosslinked polymers are more resistant to coalescing when they flocculate that the emulsions in which the surfactants they are not crosslinked, and in some cases they can be dispersed again to its original state.

\hbox{Atlas G5000
ó GLO5 al mismo nivel de tensioactivo usado en la primera
emulsión.}

An aqueous emulsion at pH above 7 with an internal phase volume of 50% was prepared from s-metolachlor mixed with 2% CX-300, using the polymeric surfactant of Example 2f with 1% w / w Regarding the oil phase. The polymer was crosslinked by lowering the pH of the emulsion below 3 and stirring for 3 hours at 20 ° C. Said emulsion was compared with control samples that were prepared with the same uncrosslinked polymeric surfactant, and with

 \ hbox {Atlas G5000
or GLO5 at the same level of surfactant used in the first
emulsion.} 

The emulsions were diluted to 5% of internal phase volume in sodium sulfate solution for provide 0.7 moles • 1 of salt in the continuous phase. After letting stand for 30 minutes, all emulsions had flocculated Emulsions prepared with crosslinked polymer, Atlas G5000 and GLO5 had sedimented as flocculated drops while the emulsion prepared with the corresponding uncrosslinked polymer They had sedimented and started to coalesce. For each sample the serum that was above the sediment was removed and it was replaced with deionized water to simulate dilution in a great excess of water Then the samples were shaken vigorously at hand for 1 minute and the emulsions by optical microscopy. The emulsion prepared with the corresponding uncrosslinked polymer is not they re-emulsified after coalescence and Emulsion prepared with GLO5 was not reflocated satisfactorily. The emulsions prepared with Atlas G5000 had suffered an increase significant in drop size and were still partially flocculated On the contrary, the emulsion prepared according to the invention was dispersed cleanly and suffered no significant change in droplet size.

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Example 8

An aqueous emulsion was prepared at pH above of 7 with an internal phase volume of 50% from one Lambda-Cihalotrina and Solvesso 200 solution (1: 1) mixed with 1% CX-300, using the polymeric surfactant of Example 2f with 1% w / w phase oilseed

The polymeric surfactant was crosslinked. by decreasing the pH of the emulsion to below 3 and stirring for 3 hours at 20 ° C. Said emulsion was compared with control samples that were prepared with the same surfactant polymer without cross-linking, and with Atlas G5000 or GLO5 at the same level of surfactant used in the first emulsion.

The emulsions were diluted to 5% of internal phase volume in sodium sulfate solution for provide 0.1 mol • L -1 salt in the continuous phase and they were heated to 50 ° C for 30 minutes without stirring, after which all the emulsions had flocculated. Emulsions prepared according to the invention using the surfactant crosslinked polymer, Atlas G5000 and GL05 had sedimented as flocculated drops while the emulsion prepared with the corresponding non-crosslinked polymeric surfactant had sedimented and had begun to coalesce. For each sample you removed the serum that remained above the sediment and replaced with deionized water to simulate dilution in a large excess of Water. Then the samples were vigorously shaken to hand for 1 minute and the emulsions were studied by Optical microscopy. The emulsion prepared with the corresponding non-crosslinked polymeric surfactant is not they re-emulsified after coalescence and emulsions prepared with AtlasG5000 were not refloculated satisfactorily. On the contrary, the prepared emulsion of according to the invention using crosslinked polymeric surfactant had begun to redispersed and required another 10 minutes of agitation to redispersed in drops. The emulsion had not suffered No significant change in droplet size.

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Example 9

Examples 9 and 10 demonstrate that emulsions according to the present invention prepared using crosslinked polymers are beneficial for formulating Suspo-emulsions due to improved stability and that a smaller number of different surfactants is needed in comparison with emulsions in which the surfactants are not crosslinked

An aqueous emulsion with a volume of 50% internal phase from fenpropidine mixed with 1% p / p of HDIT using the polymeric surfactant of Example 2f with a 1% w / w with respect to the oil phase. The polymeric surfactant was crosslinked by stirring the emulsion at 50 ° C for 3 hours. Was prepared a mixture of the polymeric surfactant emulsion crosslinked with a picoxystrobin suspension concentrate (dispersed with Morwet D425) to give rise to a 25% suspo-emulsion w / w of fenpropidine - 10% w / w of picoxystrobin. This formulation does not  showed signs of crystal growth of picoxystrobin during 14 days of storage with temperature cycles (20-40 ° C) compared to a similar suspo-emulsion in which fenpropidine is emulsified with SCI 0.1 and Span 80, where the particles of picoxystrobin grew from irregular ground particles to form large plaque-shaped crystals for 14 days of storage with temperature cycles.

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Example 10

An aqueous emulsion was prepared at pH less than 7 with an internal phase volume of 50% from a product of metolachlor consisting of 88% s-metolachlor and 12% metolachlor mixed with 1% of CX-300, using the polymeric surfactant of Example 2f at 4% w / w with respect to the oil phase. He polymeric surfactant was crosslinked by a decrease in Emulsion pH up to below 3 and stirring for 3 hours at 20 ° C.

The emulsion was mixed with a concentrate of copper-mesotrione suspension, which had been dispersed with the same polymeric surfactant used for the emulsion, to give rise to a suspo-emulsion of the 20% p / p copper-mesotrione -25% p / p of s-metolachlor. This Suspo-Emulsion It was stirred for 12 hours without any change in stability, compared to similar suspo-emulsions formulated with emulsions prepared from non-surfactants reticulates that presented significant heterofloculation of the particles of s-metolachlor and copper-mesotrione.

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Examples 11a to 11z

The following examples serve to demonstrate that the reactive polymeric surfactants can be used in the preparation of polyurea microcapsules using the in situ and two-phase processes described below. Details are shown in Table 3.

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Emulsion Preparation

Both for the in situ process and for the two phases, the first stage was the preparation of an emulsion consisting of a hydrophobic oil phase, typically with an internal phase volume of between 25 and 50%. The internal phase contained 10% w / w of a mixture of TDI and PMPPI, at predetermined mass ratios between 3: 1 and 1: 1. The organic phase was mixed thoroughly using a Silverson or Ystral mixer in an aqueous phase that typically consisted of 1-4% w / w reactive polymeric surfactant relative to the internal phase dissolved in water.
deionized

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Preparation of microcapsules

The microcapsules were then prepared from the emulsion both by the in situ method and by the two-phase method:

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On-site process

The emulsion was heated to 50 ° C for approximately 3 hours, with gentle agitation provided by a paddle shaker or rotating the bowl. It hydrolyzed a proportion of isocyanate groups at the interface of the oil-water emulsion to generate amino groups that reacted rapidly with non-hydrolyzed isocyanate to form the walls of the microcapsules.

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Two phase process

A 10% w / w aqueous solution of diethylenetriamine (DETA) drop by drop at emulsion at temperature environment with moderate agitation. The amount of DETA added corresponded to an equimolar number of amino groups to groups isocyanate The DETA was disseminated through the aqueous phase until drops of oil, where he reacted at the interface with groups isocyanate to form the walls of the microcapsules.

3. 4

35

36

In the "Observations" column of the Table 3:

(i) "Not flocculated" describes a suspension of capsules in which less than 1% of the capsules are considered they are flocculated when viewed by optical microscope, and "moderately flocculated" describes a capsule suspension in which less than 50% of the capsules are flocculated and the flocculated groups do not contain more than 20 capsules, (ii) "Drops robust "describes microcapsules that maintain their shape without warp or break when a sample of the suspension is dried in air at room temperature.

Note (b) of Example 11l indicates that the internal phase was a 63% w / w solution of 5i-cyhalothrin in
Solvesso200.

Note (c) of Example 11i indicates that the phase internal was a 63% w / w solution of Teflutrin in Solvesso200.

Claims (11)

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1. A process for the production of an emulsion oil-in-water that has a phase discontinuous oilseed and a continuous aqueous phase, a process that comprises a cross-linking reaction step between (i) a polymeric stabilizer of formula (I) which is a copolymer of random graft or a block copolymer and comprising a series of vinyl monomers that are not exclusively esters vinyl or its hydrolyzed products, and that is soluble or dispersible in the continuous phase 37 where Z is a group methoxy polyethylene glycol; R1, R and R2 are independently H or methyl; X is a hydrophilic functional moiety; L is a residue that contains a crosslinking group capable of suffering nucleophilic crosslinking or condensation reactions in the interface of the dispersed and continuous phases of said emulsion, in wherein said crosslinking group is selected from -OH; -NHA in where A is hydrogen or C 1 -C 4 alkyl; Y -COOH or a salt thereof; And it is a hydrophobic residue; the value of e goes from 0.005 to 0.33; the value of f ranges from 0.05 to 0.4; and the value of g goes from 0.1 to 0.9; Y (ii) one or more substances dissolved in the phase discontinuous liquid oilseed that reacts with the group crosslinker of functional moiety L; whenever when the group crosslinker of the residue L is a reactive acid group, the substance (ii) have its corresponding reactive group isocyanate, aziridine or carbodiimide 2. A process according to claim 1, wherein in the polymer stabilizer of the formula (I): (i) R1 is hydrogen or methyl and X carries a hydrophilic functional moiety selected from -SO_ {3}; polyethylene glycol optionally protected at the ends with alkyl C 1 -C 4; -COOH and a salt thereof; carboxybetaine; sulfobetaine; a quaternary ammonium salt -N + R 3 3C in which R 3 is H or alkyl C 1 -C 4; and -CH 2 CH 2 OH; or R1 is hydrogen and X is phenyl substituted with a hydrophilic moiety selected from -SO 3 -; polyethylene glycol optionally protected at the ends with alkyl C 1 -C 4; -COOH and a salt thereof; carboxybetaine; sulfobetaine; a quaternary ammonium salt -N + R 3 C in which R 3 is H or alkyl C 1 -C 4; and -CH 2 CH 2 OH; (ii) R is hydrogen or methyl and L carries a group crosslinker selected from -OH; -NHA where A is hydrogen or C 1 -C 4 alkyl; and -COOH and a salt of same; or R is hydrogen and X is phenyl substituted with a group crosslinker selected from -OH; -NHA where A is hydrogen or C 1 -C 4 alkyl; and -COOH and a salt of same; Y (iii) R2 is hydrogen or methyl; and carries a hydrophobic moiety selected from -CO-O - (- Si (CH 3) 2 O -) n in where n goes from 3 to 20; -CO-O-polypropylene glycol; -CO-O-A where A is a C 1 -C 12 alkyl group, a group cycloalkyl, an alkylcycloalkyl group, an aralkyl group or a rented group; and -CONHB where B is an alkyl group C 5 -C 12; or R2 is hydrogen and X is phenyl substituted with a hydrophobic functional moiety selected from -CO-O - (- Si (CH3) 2
O -) n where n ranges from 3 to 20; -CO-O-polypropylene glycol; -CO-O-A where A is a C 1 -C 12 alkyl group, a group cycloalkyl, an alkylcycloalkyl group, an aralkyl group or a rented group; and -CONHB where B is an alkyl group C 5 -C 12; 3. A process according to claim 2, wherein in the polymeric stabilizer of formula (I): (i) the group 38 derives from one or more monomers selected from acid 2- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) ethanoic acid, 2- (trimethylammonium) ethyl methacrylate salt, acid 3- (N, N-dimethyl-N- (2-methacryloxyethyl) ammonium) propyl sulfonic acid, sodium salt of methacrylic acid, succinate mono-2- (methacryloxy) ethyl, mono-methoxy mono-methacrylate poly (ethylene glycol), acid styrene-4-sulfonic chloride 4-vinylbenzyl trimethyl ammonium, 2-N-morpholinoethyl methacrylate 2-methacryloxyethylphosphonate and acid 2-acrylamido-2-methylpropane sulfonic; (ii) the group 39 derives from one or more monomers selected from 2-aminoethyl methacrylate, 2-hydroxyethyl methacrylate, the sodium salt of methacrylic acid, succinate mono-2- (methacryloxy) ethyl, poly (propylene glycol) mono-methacrylate, 2-methoxy-4-vinylphenol,  4-vinylbenzyl alcohol, 4-vinylphenol, 2,6-dihydroxymethyl-4-methoxystyrene, 3,5-dimethoxy-4-hydroxystyrene, chloride 2-hydroxy-3-methacryloxypropyl trimethyl ammonium methacrylate 3-chloro-2-hydroxypropyl, 3-hydroxypropyl methacrylate, methacrylate 2-hydroxy-3-phenoxypropyl, diethylene glycol mono-methacrylate, methacrylate 2,3-dihisroxypropyl glycoside of 2-methacryloxyethyl, sorbitol methacrylate, 2-methacryloxyethyl ester of caprolactone, 4-hydroxybutyl methacrylate, methacrylate 2-hydroxypropyl, 4-amino styrene, 2- (iso-propylamino) ethylstyrene, acid 4-N- (vinylbenzyl) aminobutyric acid, hydrochloride from 3- (N-Styrylmethyl-2-aminoethylamino) -propyltrimethoxysilane, N- (3-methacryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, 4-vinylbenzoic acid, acid 4 - ((3-methacryloxy) propoxy) benzoic and mono- (2- (methacryloxy) ethyl) phthalate; Y (iii) the group 40 derives from one or more of the following monomers: methyl methacrylate, poly (dimethylsiloxane) mono-methacrylate, mono-methacrylate mono-methoxypoly (propylene glycol), esters of vinyl, vinyl halogens, styrene and styrene optionally replaced. 4. A process according to any of the preceding claims, wherein (a) when the crosslinking group of the remainder L is hydroxyl or thiol, the substance (ii) that reacts with the groups Functional is difunctional or polyfunctional and is an isocyanate, ester or epoxide; or (b) when the crosslinking group of the remainder L is amino, the substance (ii) that reacts with the functional groups It is difunctional or polyfunctional and is an isocyanate, acetoacetoxy, aldehyde, acrylate, vinylsulfone or epoxide. 5. A process according to claim 4, in which the isocyanate is selected from diisocyanate of tolylene and the isomers thereof, phenylene diisocyanate and the isomers thereof, biphenylene diisocyanates and the isomers and derivatives thereof, polymethylene polyphenylene isocyanates, hexamethylene diisocyanate and isomers thereof e isophorone diisocyanate. 6. A process for the production of microcapsules comprising a process according to any of claims 1 to 3, wherein the substance (ii) dissolved in the discontinuous liquid phase is a monomer or pre-polymer capable of reacting to form a microcapsule coating wall. 7. A process according to claim 6, in which the monomer or pre-polymer is select from aromatic diisocyanates, polyisocyanates aromatic and optionally urea prepolymers etherified-formaldehyde. 8. A process according to any of the preceding claims, wherein the polymeric stabilizer it comprises between 0.5 and 8 percent by weight of the phase discontinuous stabilizing. 9. A process according to claim 8, in which the polymer stabilizer comprises between 1 and 4 percent by weight of the discontinuous phase that stabilizes. 10. A process according to any of the preceding claims, wherein the discontinuous liquid phase It has an active agrochemical ingredient dissolved or dispersed in she. 11. A process according to claim 10, in which the continuous aqueous phase contains a suspension of a second active agrochemical ingredient.